Fred above says he had both, I would have to yield to him on this and I am certain mine is not an H serial. Pretty sure mine is F as well.

That said, blue 15300's are not exactly plentiful. Unless you want to wait quite a bit, assuming there is in fact a difference, you may not have many options at your disposal here. Good luck either way, it really is a great piece!

Yes, both of my F and H serial 15300s had the same butterfly bracelets. I agree with Nick that you may not have much choice given not many mint 15300s come to the market and when I sold my blue, I had a lot of interests.